Refrigerator freshener

ABSTRACT

A refrigerator freshening device includes an air-permeable container, enclosing a mixture, in particulate form, of a major amount of activated carbon and a minor amount of an odor-absorbing zeolite. The activated carbon is preferably characterized by a good distribution of large and small pores, at least 30 percent of the pores having a diameter of from about 15 to less than about 50 Å and the zeolite by a strong organophilic character and a surface area of at least about 400 square meters per gram. The combination of particulate adsorbent materials preferably includes from about 5 to about 25 percent of the zeolite and from about 75 to about 95 percent of the activated carbon. The device preferably includes a front panel. a back panel, and a package constructed of flexible, porous material enclosing absorbent, wherein the front panel receives the back panel in nesting relationship and encloses the package of adsorbent material. Hooks are preferred to suspend the device freely within a refrigerator. The device maintains a fresh environment within a refrigerator, by acting immediately to delay the buildup of odors when aromatic foods are placed therein and continues to maintain low odor levels for extended times.

This application is a continuation of U.S. patent application Ser. No.08/560,747 filed Nov. 20, 1995, now abandoned, which in turn was acontinuation of Ser. No. 08/354,935 filed Dec. 13, 1994, now U.S. Pat.No. 5,468,447, which in turn was a continuation of Ser. No. 08/159,732,filed Nov. 30, 1993, now abandoned.

TECHNICAL FIELD

The invention relates to an improved device for maintaining a freshenvironment within a refrigerator, and especially to one which actsimmediately to delay the buildup of odors when aromatic foods are placedtherein and continues to maintain low odor levels for extended timeperiods.

The odors of various foods, such as onion, garlic, strong cheeses, gameymeats, and the like, often fill the refrigerator with a bouquet ofstrong and incompatible aromas. This presents the home cook with aproblem--beyond mere unpleasantness--of the blending of odors andflavors among the various foods stored in the refrigerator. Long termstorage is certainly a problem, but one particularly troublesomesituation is the short term storage of foods prepared in advance of orbrought to a dinner party or other social gathering. The desirable aromaof one dish can, by sharing its essence, diminish the character ofanother food.

Many techniques have been employed over the years to reduce the problem,and the most important of these is simply to use care when wrappingfoods for refrigerator storage. However, even with care, some odors arejust too strong to deal with and something more than discretion isrequired. Other techniques have employed various odor eaters, such asbaking soda, active carbon, certain zeolites, and the like. Each ofthese seems to provide some help, but there remains a need for a deviceand a technique that can moderate the level of odor initially as well asover time.

BACKGROUND ART

The art of fresheners for refrigerators is unique to itself because ofthe wide variety of strong odors that are typically involved and theeffect that they can have on the foods stored. This is clearly differentfrom the art of air fresheners in general which often remove onlycertain types of odors or try to cover up some with others--perfumes andfragrances, no matter how pleasant, can't be employed. The additiveeffect of these materials with the naturally evolved odors from thecontents of the refrigerator, will not necessarily be pleasant.Moreover, such additives can alter the desired flavor and aroma ofstored materials. For refrigerators, odor controllers typically employabsorbent or adsorbent materials such as baking soda (NaHCO₃), activatedcarbon, zeolites, clays and other minerals, and the like. Combinationsof various of these materials have also been used for specifiedpurposes, but no combination has been known to provide the desired shortterm and long term effects.

In U.S. Pat. No. 3,990,872, Cullen describes an absorbent package madeof spunbonded olefin walls holding a particulate adsorbent material. Theadsorbent materials identified are silica gel, activated carbon,bentonite, montmorillonite, molecular sieve, and any other type ofdesiccant or adsorbent material desired. No direction is given forrefrigerator use.

U.S. Pat. No. 4,401,447, to Huber describes an adsorbent unit for useinternally of a refrigerant system, but not a refrigerator per se. Thispatent also provides a wide variety of choices for adsorbents with noparticular preference for any. The absorbent may selectively include,without limitation, adsorbents such as silica gel, metal, aluminosilicate, alumina, calcium sulfate, activated charcoal, molecular sieve,or any other desired compound in bead, pellet or granular form.

In U.S. Pat. No. 4,437,429, Goldstein et al. disclose, not arefrigerator freshener, but a litter for cats or other small animals.Their composition of a zeolite, such as clinoptilolite, in combinationwith a clay or other sorptive, non-colloidal granular aluminosilicate,is said to have extended life as compared to litters made of clay alone.

In U.S. Pat. No. 4,534,775 and its divisional U.S. Pat. No. 4,604,110,Frazier describes an air filter element--of the type typically referredto as a room air freshener--for use with a fan for drawing room airthough it to remove odors. The filter element includes a dry mixture ofsilica gel, activated carbon, and a zeolite, all preferably inparticulate form, packed into a filter body so as to minimize the porevolume or void space. The dry mixture can be impregnated with a liquidfor inhibiting the growth of microorganisms. While each of thecomponents of the dry mixture is disclosed to be used at a level of fromabout 10 to 80 weight percent, it is preferred to employ essentiallyequal weights of each. The patentee discloses that the materialstogether synergistically remove a wide spectrum of household odors.

In U.S. Pat. No. 4,795,482, Gioffre et al. describe reducing odorsattributable to organic molecular species, through the use of acrystalline molecular sieve material having at least 90% of itstetrahedral oxide units as SiO₂ tetrahedra, having pore aperturesnominally at least 5.5 Å in diameter, and meeting other criteria. Thisclass of materials is said to include zeolites as well as the so-calledsilica polymorphs. Comparisons are cited between these molecular sieves(exemplified as zeolites), activated charcoal, silicalite, silica gel,NaHCO₃, and mixtures of the zeolite with silicalite. Combinations ofcharcoal and zeolite were not tested.

In U.S. Pat. No. 4,826,497, Marcus et al. disclose a fibrous absorbentarticle (disposable diapers, catamenial devices, wound dressings, etc.)containing a suitable zeolite having the ability to deodorize withrespect to bodily fluids, even in the presence of water. Comparisons aremade between several zeolites, activated charcoal, silica gel,silicalite, NaHCO₃, and various combinations other than the combinationof activated charcoal and zeolite.

Thus, despite the wide range of prior art describing and comparingvarious gas adsorbing materials for use in various deodorizingsituations, it has not been previously recognized that combinations ofcrystalline aluminosilicate zeolite adsorbents, in minor amount, with amajor amount of activated charcoal, would have particular utility for arefrigerator freshener--particularly one which fills the need for rapidresponse in combination with long acting odor reduction.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and its advantages will bebetter appreciated from the following detailed description, especiallywhen read in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a preferred form of air freshener of theinvention freely hanging within a refrigerator compartment;

FIG. 2 is an exploded perspective view, partially cut away, showing apreferred form of refrigerator freshener of the invention;

FIG. 3 is a front elevational view of the refrigerator freshener shownin FIG. 2;

FIG. 4 is a cross-sectional view of a preferred form of refrigeratorfreshener of the invention, taken along line 4--4 in FIG. 3; and

FIG. 5 is an enlarged view of detail of the refrigerator freshener shownin FIG. 3.

DISCLOSURE OF THE INVENTION

It is an object of the invention to provide an improved device formaintaining the freshness of the air within a refrigerator.

It is another object of the invention to provide an improved device formaintaining the freshness of the air within a refrigerator byimmediately eliminating odors to prevent their buildup after placingodorous foods in the refrigerator.

It is a more specific object of the invention to provide an improveddevice for maintaining the freshness of the air within a refrigerator,especially shortly after placing therein highly odorous foods, such asonion, garlic, strong cheeses, aged meats, and the like.

It is yet another object of the invention to provide a device and atechnique for its use which can moderate the level of odor in arefrigerator both when storing foods both initially and over extendedtimes.

These and other objects are realized by the present invention whichprovides both a device and a technique for its use which can moderatethe level of odor initially as well as over time. The device, in one ofits broader aspects comprises an air-permeable container enclosing amixture, in particulate form, of a major amount of active carbon and aminor amount of an odor-absorbing zeolite. The technique or process ofthe invention comprises suspending the container, as described above,from a refrigerator shelf to permit the normal movement of air withinthe refrigerator to pass by and be deodorized by the active carbon andthe zeolite.

The combination of particulate adsorbent materials preferably includesfrom about 5 to about 25 percent of the zeolite and from about 75 toabout 95 percent of the activated carbon. Unless otherwise indicated,all parts and percentages used in the specification, are based on theweight of the ingredient or material at the indicated stage ofprocessing.

The device preferably includes a front panel. a back panel, and apackage constructed of flexible, porous material enclosing absorbent,wherein the front panel receives the back panel in nesting relationshipand encloses the package of adsorbent material. Hooks are preferred tosuspend the device freely within a refrigerator.

INDUSTRIAL APPLICABILITY

The invention will be described below with specific reference to apreferred embodiment as illustrated in FIGS. 1 through 5. Therefrigerator freshening device 10 of the invention preferably includeshooks 12 and 12' to facilitate hanging it from a wire shelf element 14in a refrigerator 16 as shown in FIG. 1.

The ability to freely suspend the device 10 in this manner permits afree circulation of air around and into contact with it by maintainingit in a position off of the storage surfaces. The device 10 permits bulkflow of air within the refrigerator 16 to come into contact with it at asufficient rate and for a sufficient time period to immediately have asignificant odor reducing effect on odors emanating from foods.Accordingly, when a variety of foods are prepared ahead of time for anevent and placed in the refrigerator, the refrigerator freshening deviceof the invention will help each food maintain its own natural flavor andaroma, unadulterated by the odors of the other foods.

FIG. 2 is an exploded view showing the principal structural features ofthe refrigerator freshener of the invention. A front panel 20 receivesback panel 30 in nesting relationship, enclosing absorbent package 40.

The front panel 20 includes a rectangular front wall member 22 (see FIG.4), and four side wall members 23. The front wall member has an outsidesurface 24 (see FIGS. 3 and 4) and an inside surface 25. The detail ofFIG. 5 shows the grid structure provided by ribs 26 and holes 27 whichextend through the front wall member from the inside surface to theoutside surface. Extending outwardly from the inside surface, andpositioned near each of the side wall members 23, are posts 28 havingholes 29 therein. As will be explained below, the posts function withthe package 40 and complimentary means on the back panel to suspend thepackage.

The back panel 30 includes a rectangular rear wall member 32, and fourside wall members 33. The rear wall member has an outside surface 34(see FIG. 4) and an inside surface 35 with a grid structure 36 which issimilar in structure to that of the front panel. Posts 38 extendoutwardly from the inside surface 35 of back panel 30. The posts 38 arelocated at suitable positions to enable engagement with the holes 29 inposts 28 on the front wall member. The posts 38 should be of similardiameter as the holes, optionally with a slight taper or other meansfacilitating mechanical or frictional interlock, to permit a secure fit.The outer dimension of the rear panel 30 is defined by wall members 33and is selected to nest within the opening defined by the wall members23 of the front panel 20. It will be apparent, however, that the postand wall panel dimensions can be varied as desired to achieve thenecessary structural integrity of the unit with the package 40 suspendedbetween the porous front and rear panel members.

The package 40 includes a porous outer wall member 42 which encloses agranular adsorbent 44 composition which comprises a major amount ofactivated carbon and a minor amount of zeolite. Preferably, the porousouter wall member should have a porosity at least sfuuficient to permitrefrigerator air to freely flow into and out of the package but not sogreat as to permit dust from the particulate adsorbents to escapethrough the pores. Preferably, the permeability will be within the rangeof up to about 100 gurley seconds, e.g. from about 5 to about 25 gurleyseconds.

In practice, porous paper and nonwoven polymeric felt materials such asemployed for teabags, coffee filters, and as specifically available foruse in making pouches for odor adsorbents, can be employed. A preferredmaterial is made of a nonwoven fabric comprised of polyester andpolypropylene, e.g. at a ratio of 63.3 parts polyester to 36.7 parts ofthe polypropylene. The package shown in the drawing is made by cuttingtwo thicknesses of a heat-sealable nonwoven fabric, which is sealedaround the entire periphery to enclose particulate adsorbent 44 andprovide a compressed marginal edge 46. Holes as needed, e.g. 47 and 47',can be provided to suspend the package from posts 28 between the frontand rear panels.

The surprisingly good combination of effectiveness for initial responseto strong odors and extended effectiveness against accumulating odorsachieved by the refrigerator freshener of the invention is believed dueto the combination of the activated carbon and the zeolite. The loosepacking of the particulate materials in the package 40, its suspensionbetween the porous front and rear wall members 22 and 32, and thesuspension of the device by hooks 12 and 12' in the freely circulatingair in a refrigerator enhance this effectiveness. Preferably, theparticulate materials will have a bulk density of from about 0.3 toabout 0.6 grams per cubic centimeter.

Preferred forms of activated carbon are characterized by a gooddistribution of large and small pores, preferably with at least 30percent of the pores having a diameter of from about 15 to less thanabout 50 Å, most preferably from about 15 to about 20 Å, and onepreferred form is available from Calgon as BPL 633 16 granular carbon.

Preferred forms of zeolite are characterized by a strong organophiliccharacter and a surface area of at least about 400 square meters pergram, and one preferred form is available from UOP as Abscents®deodorizing powders. In general, the preferred zeolites are thosecrystalline molecular sieve materials having at least 90% of theirtetrahedral oxide units as SiO₂ tetrahedra, and having pore aperturesnominally at least 5.5 Å in diameter, such as described in theabove-mentioned U.S. Pat. No. 4,795,482, which is hereby incorporated inits entirety.

Preferred combinations of these granular adsorbent materials willconsist essentially of a zeolite and activated carbon, including fromabout 5 to about 25 percent of the zeolite and from about 75 to about 95percent of the activated carbon. The most preferred combinations willcontain from about 7 to about 15 percent of the zeolite, e.g. about 9percent, with from about 85 to about 93 percent of the activated carbon.

The above description is intended to enable the person skilled in theart to practice the invention. It is not intended to detail all of thepossible modifications and variations which will become apparent to theskilled worker upon reading the description. It is intended, however,that all such modifications and variations be included within the scopeof the invention which is defined by the following claims. The claimsare meant to cover the indicated elements and steps in any arrangementor sequence which is effective to meet the objectives intended for theinvention, unless the context specifically indicates the contrary.

I claim:
 1. A refrigerator freshening device, which is capable offreshening the air in a refrigerator and comprises:a front panelincluding a rectangular front wall member and four side wall members,the front wall member having an outside surface, an inside surface, anda grid structure Including holes which extend through the front wallmember from the inside surface to the outside surface; a back panel,including a rectangular rear wall member and four side wall members, therear wall member having an outside surface, an inside surface, and agrid structure including holes which extend through the rear wall memberfrom the inside surface to the outside surface; a package constructed offlexible, porous material enclosing an absorbent, in particulate form,consisting essentially of from 75 to 95 percent of active carbon havingpores wherein at least 30 percent of the pores have a diameter of fromabout 15 to less than about 50 Å and from 5 to 25 percent of anodor-absorbing zeolite having an organophilic character and a surfacearea of at least 400 square meters per gram; and wherein the front panelreceives the back panel in nesting relationship and encloses the packageof adsorbent material.
 2. A process for maintaining a fresh environmentwithin a refrigerator, by acting immediately to delay the buildup ofodors when aromatic foods are placed therein and continuing to maintainlow odor levels for extended times, comprising:providing anair-permeable container having enclosed therein an absorbent, inparticulate form, consisting essentially of from 75 to 95 percent ofactive carbon having pores wherein at least 30 percent of the pores havea diameter of from about 15 to less than about 50 Å and from 5 to 25percent of an odor-absorbing zeolite having an organophilic characterand a surface area of at least 400 square meters per gram; andpositioning the container within a refrigerator to permit the normalmovement of air within the refrigerator to pass by and be deodorized bythe active carbon and the zeolite.